<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Parent</title>
</head>
<body>
<div>
    <iframe src="./frame.html"></iframe>
</div>

<a href="./child.html" target="_blank">open window</a>

<button>parent</button>

</body>
</html>
